[doc] chain: Declare BLOCK_VALID_HEADER reserved

src/chain.h

@@ -95,8 +95,8 @@ enum BlockStatus: uint32_t {
     //! Unused.
     BLOCK_VALID_UNKNOWN      =    0,
 
-    //! Parsed, version ok, hash satisfies claimed PoW, 1 <= vtx count <= max, timestamp not in future
-    BLOCK_VALID_HEADER       =    1,
+    //! Reserved (was BLOCK_VALID_HEADER).
+    BLOCK_VALID_RESERVED     =    1,
 
     //! All parent headers found, difficulty matches, timestamp >= median previous, checkpoint. Implies all parents
     //! are also at least TREE.
@@ -117,7 +117,7 @@ enum BlockStatus: uint32_t {
     BLOCK_VALID_SCRIPTS      =    5,
 
     //! All validity bits.
-    BLOCK_VALID_MASK         =   BLOCK_VALID_HEADER | BLOCK_VALID_TREE | BLOCK_VALID_TRANSACTIONS |
+    BLOCK_VALID_MASK         =   BLOCK_VALID_RESERVED | BLOCK_VALID_TREE | BLOCK_VALID_TRANSACTIONS |
                                  BLOCK_VALID_CHAIN | BLOCK_VALID_SCRIPTS,
 
     BLOCK_HAVE_DATA          =    8, //!< full block available in blk*.dat